1. FIELD OF THE INVENTION
The invention is directed to throttle valves used in a conventional internal combustion engine for introducing additional air into the intake manifold during cranking.
2. DESCRIPTION OF THE PRIOR ART
In most conventional internal combustion engines, a quantity of air is introduced into the intake manifold before ignition through the process of "cranking" the engine, by alternately depressing and releasing the accelerator pedal thereby entraining fuel in the resultant flow of air through the open throttle plate and past the throttle plate when closed. This pedal is connected to the throttle valve through the appropriate linkages and opens in response to the pedal position, thereby allowing air to flow between the throttle valve and the throttle body bore, and into the intake manifold. While this system ultimately introduces sufficient air to start the engine, it would be advantageous to provide a throttle valve which would automatically introduce a greater amount of air during cranking, and then close and introduce the same amount of air to the intake manifold as would a conventional throttle at a particular throttle position. This system would preferably include a flapper valve mounted on the throttle, said flapper valve opening and closing a hole in the throttle plate in response to the pressure differential across the valve.
The prior art is replete with carburetors employing throttle valves of different configurations containing holes therein for specific purposes. One such carburetor is shown in U.S. Pat. No. 2,080,440 issued to H. T. Scott. This patent shows a throttle valve formed with equidistantly spaced minute orifices to ensure complete atomization or pulverization of the fuel and to prevent the movement of globules of fuel past the throttle valve and into the intake manifold.
Another carburetor of note is shown in U.S. Pat. No. 3,437,320 issued to Brooks Walker and Frank W. Kertell. This patent describes a butterfly valve containing at least one aperture therein for providing air for idling when the valve is closed. This particular butterfly valve configuration may be used to reduce smog-producing components in the exhaust of an internal combustion engine.
German Pat. No. 433,083 shows a throttle valve having a hole in one side. A flapper valve having a larger diameter than the throttle valve is connected to said throttle valve and is capable of movement toward and away from the hole in cooperation with the air flow and a flow line.
U.S. Pat. No. 3,907,944 issued to Masahiko Nakada describes a choke control system for internal combustion engines including a diaphragm box having a liquid chamber bisected by a partition wall. The box is connected to a choke valve by a rod, with the wall containing an orifice and a check valve. When the check valve is in its opened position as shown in FIG. 2, no vacuum is applied in the diaphragm chamber. When the valve is in its closed condition (FIG. 3), vacuum does act in the diaphragm chamber. It should be noted, however, this check valve is arranged to be opened or closed in accordance with the operating temperature conditions of the engine.
Other references showing carburetor throttles are U.S. Pat. Nos. 2,658,734; 3,298,677; 3,523,680; and 3,759,489.
Therefore, a review of prior art has failed to uncover, and the inventor is unaware of, a reference showing a flapper blade attached to a throttle valve which is closed when a pressure differential occurs across the blade.